Assessment of Type of Allergy and Antihistamine Use in the Development of Glioma

Abstract

Background: Allergies have been associated with decreased risk of glioma; but, associations between duration and timing of allergies, and antihistamine use and glioma risk have been less consistent. The objective was to investigate this association by analyzing types, number, years since diagnosis, and age at diagnosis of allergies, and information on antihistamine usage, including type, duration, and frequency of exposure.Methods: Self-report data on medically diagnosed allergies and antihistamine use were obtained for 419 glioma cases and 612 hospital-based controls from Duke University and NorthShore University HealthSystem.Results: High-and low-grade glioma cases were statistically significantly less likely to report any allergy than controls (OR ¼ 0.66, 95% CI: 0.49-0.87 and OR ¼ 0.44, 95% CI: 0.25-0.76, respectively). The number of types of allergies (seasonal, medication, pet, food, and other) was inversely associated with glioma risk in a dose-response manner (P value for trend < 0.05). Age at diagnosis and years since diagnosis of allergies were not associated with glioma risk. Oral antihistamine use was statistically significantly inversely associated with glioma risk, but when stratified by allergy status, remained significant only for those with high-grade glioma and no medically diagnosed allergy.Conclusions: All types of allergies appear to be protective with reduced risk for those with more types of allergies. Antihistamine use, other than in relationship with allergy status, may not influence glioma risk.Impact: A comprehensive study of allergies and antihistamine use using standardized questions and biological markers will be essential to further delineate the biological mechanism that may be involved in brain tumor development. Cancer Epidemiol Biomarkers Prev; 20(2); 370-8. Ó2011 AACR.

Approaching a Scientific Consensus on the Association between Allergies and Glioma Risk: A Report from the Glioma International Case-Control Study

“…The impact of antihistamine use is difficult to disentangle from that of allergies, as these factors are highly correlated, and few individuals without allergies use antihistamines regularly. Previously, McCarthy et al reported an OR of 0.76 for the association between any oral antihistamine use versus none (95% CI: 0.59–0.99), but they did not adjust for allergy status and their result could, therefore, be confounded by the effect of allergies (17). In our prior studies, we have observed an increased risk for glioma associated with antihistamine use, particularly among individuals with allergic conditions (38–40); however, other studies have found either no association or a protective effect (18, 41).…”

“…One commonly proposed hypothesis on how allergies may confer protection against glioma revolves around the idea that allergies and other atopic conditions may represent a heightened state of immunosurveillance (2, 11, 17, 42). The presence of a hyperactive immune system may subsequently prohibit abnormal cell growth or proliferation, but the specific mechanism by which heightened immunosurveillance could help abate tumor growth remains unexplained.…”

“…These associations have been examined using single- [i.e., (11)], multi-site [i.e., (12–14)], and nested case-control studies [i.e., (15, 16)], prospective cohort studies [i.e., (3)], and meta-analyses [i.e., (1, 2, 7)]. Additionally, the observed inverse association between allergies and glioma has remained consistent across studies with different exposure assessment strategies, such as self-reported allergy status (3), self-reported physician-diagnosed allergies (12, 13, 17–19), number of allergy types (12, 17), and allergy-related biomarkers, such as Immunoglobulin E [overall (4, 11, 16, 20), pre-diagnostic (16, 21), and/or allergen-specific (11, 15, 16)], soluble CD23 levels (22), and polymorphisms in allergy-related genes (23–26). As the literature approaches a consensus on the relationship between allergies and glioma risk, our large consortium, the Glioma International Case-Control Study (GICC), provides an unprecedented opportunity to not only confirm the previously reported associations between atopy and glioma in the largest available study population, but also to hone in on the specific role of respiratory allergies.…”

Risk factors for gliomas. An extensive review

“…In a study risk decreased with 31-45% for every new atopic condition (98). Antihistamine usage was not correlated with this risk (101). In most studies the levels of IgE, an objective assessment tool for allergic conditions, correlated with the risk for glioma.…”

“…In a meta-analysis published in 2011, by Chen and coworkers, that included 12 studies, authors conclude that allergies could significantly decrease the risk of gliomas (102). Moreover, some studies have shown that, the number of allergies for a patient is directly proportional with a smaller risk (98,101). In a study risk decreased with 31-45% for every new atopic condition (98).…”